/*
 * Copyright 2002-2017 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.scheduling.config;

import java.util.concurrent.RejectedExecutionHandler;

import org.springframework.beans.factory.BeanNameAware;
import org.springframework.beans.factory.DisposableBean;
import org.springframework.beans.factory.FactoryBean;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.core.task.TaskExecutor;
import org.springframework.lang.Nullable;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
import org.springframework.util.StringUtils;

/**
 * {@link FactoryBean} for creating {@link ThreadPoolTaskExecutor} instances,
 * primarily used behind the XML task namespace.
 *
 * @author Mark Fisher
 * @author Juergen Hoeller
 * @since 3.0
 */
public class TaskExecutorFactoryBean implements
        FactoryBean<TaskExecutor>, BeanNameAware, InitializingBean, DisposableBean {

    @Nullable
    private String poolSize;

    @Nullable
    private Integer queueCapacity;

    @Nullable
    private RejectedExecutionHandler rejectedExecutionHandler;

    @Nullable
    private Integer keepAliveSeconds;

    @Nullable
    private String beanName;

    @Nullable
    private ThreadPoolTaskExecutor target;


    public void setPoolSize(String poolSize) {
        this.poolSize = poolSize;
    }

    public void setQueueCapacity(int queueCapacity) {
        this.queueCapacity = queueCapacity;
    }

    public void setRejectedExecutionHandler(RejectedExecutionHandler rejectedExecutionHandler) {
        this.rejectedExecutionHandler = rejectedExecutionHandler;
    }

    public void setKeepAliveSeconds(int keepAliveSeconds) {
        this.keepAliveSeconds = keepAliveSeconds;
    }

    @Override
    public void setBeanName(String beanName) {
        this.beanName = beanName;
    }


    @Override
    public void afterPropertiesSet() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        determinePoolSizeRange(executor);
        if (this.queueCapacity != null) {
            executor.setQueueCapacity(this.queueCapacity);
        }
        if (this.keepAliveSeconds != null) {
            executor.setKeepAliveSeconds(this.keepAliveSeconds);
        }
        if (this.rejectedExecutionHandler != null) {
            executor.setRejectedExecutionHandler(this.rejectedExecutionHandler);
        }
        if (this.beanName != null) {
            executor.setThreadNamePrefix(this.beanName + "-");
        }
        executor.afterPropertiesSet();
        this.target = executor;
    }

    private void determinePoolSizeRange(ThreadPoolTaskExecutor executor) {
        if (StringUtils.hasText(this.poolSize)) {
            try {
                int corePoolSize;
                int maxPoolSize;
                int separatorIndex = this.poolSize.indexOf('-');
                if (separatorIndex != -1) {
                    corePoolSize = Integer.valueOf(this.poolSize.substring(0, separatorIndex));
                    maxPoolSize = Integer.valueOf(this.poolSize.substring(separatorIndex + 1, this.poolSize.length()));
                    if (corePoolSize > maxPoolSize) {
                        throw new IllegalArgumentException(
                                "Lower bound of pool-size range must not exceed the upper bound");
                    }
                    if (this.queueCapacity == null) {
                        // No queue-capacity provided, so unbounded
                        if (corePoolSize == 0) {
                            // Actually set 'corePoolSize' to the upper bound of the range
                            // but allow core threads to timeout...
                            executor.setAllowCoreThreadTimeOut(true);
                            corePoolSize = maxPoolSize;
                        }
                        else {
                            // Non-zero lower bound implies a core-max size range...
                            throw new IllegalArgumentException(
                                    "A non-zero lower bound for the size range requires a queue-capacity value");
                        }
                    }
                }
                else {
                    Integer value = Integer.valueOf(this.poolSize);
                    corePoolSize = value;
                    maxPoolSize = value;
                }
                executor.setCorePoolSize(corePoolSize);
                executor.setMaxPoolSize(maxPoolSize);
            }
            catch (NumberFormatException ex) {
                throw new IllegalArgumentException("Invalid pool-size value [" + this.poolSize + "]: only single " +
                        "maximum integer (e.g. \"5\") and minimum-maximum range (e.g. \"3-5\") are supported", ex);
            }
        }
    }


    @Override
    @Nullable
    public TaskExecutor getObject() {
        return this.target;
    }

    @Override
    public Class<? extends TaskExecutor> getObjectType() {
        return (this.target != null ? this.target.getClass() : ThreadPoolTaskExecutor.class);
    }

    @Override
    public boolean isSingleton() {
        return true;
    }


    @Override
    public void destroy() {
        if (this.target != null) {
            this.target.destroy();
        }
    }

}
